Risk factors and development of machine learning diagnostic models for lateral lymph node metastasis in rectal cancer: multicentre study.

BACKGROUND: The diagnostic criteria for lateral lymph node metastasis in rectal cancer have not been established. This research aimed to investigate the risk factors for lateral lymph node metastasis and develop machine learning models combining these risk factors to improve the diagnostic performance of standard imaging. METHOD: This multicentre prospective study included patients who underwent lateral lymph node dissection without preoperative treatment for rectal cancer between 2017 and 2019 in 15 Japanese institutions. First, preoperative clinicopathological factors and magnetic resonance imaging findings were evaluated using multivariable analyses for their correlation with lateral lymph node metastasis. Next, machine learning diagnostic models for lateral lymph node metastasis were developed combining these risk factors. The models were tested in a training set and in an internal validation cohort and their diagnostic performance was tested using receiver operating characteristic curve analyses. RESULTS: Of 212 rectal cancers, 122 patients were selected, including 232 lateral pelvic sides, 30 sides of which had pathological lateral lymph node metastasis. Multivariable analysis revealed that poorly differentiated/mucinous adenocarcinoma, extramural vascular invasion, tumour deposit and a short-axis diameter of lateral lymph node ≥ 6.0 mm were independent risk factors for lateral lymph node metastasis. Patients were randomly divided into a training cohort (139 sides) and a test cohort (93 sides) and machine learning models were computed on the basis of a combination of significant features (including: histological type, extramural vascular invasion, tumour deposit, short- and long-axis diameter of lateral lymph node, body mass index, serum carcinoembryonic antigen level, cT, cN, cM, irregular border and mixed signal intensity). The top three models with the highest sensitivity in the training cohort were as follows: support vector machine (sensitivity, 1.000; specificity, 0.773), light gradient boosting machine (sensitivity, 0.950; specificity, 0.918) and ensemble learning (sensitivity, 0.950; specificity, 0.917). The diagnostic performances of these models in the test cohort were as follows: support vector machine (sensitivity, 0.750; specificity, 0.667), light gradient boosting machine (sensitivity, 0.500; specificity, 0.852) and ensemble learning (sensitivity, 0.667; specificity, 0.864). CONCLUSION: Machine learning models combining multiple risk factors can contribute to improving diagnostic performance of lateral lymph node metastasis.

Tumor Lysis Syndrome in a Patient with BRAFV600E Mutated Colon Cancer Treated with Cetuximab and Encorafenib.

Tumor lysis syndrome (TLS) is a fatal complication associated with chemotherapy. We herein report a case of TLS in a 73-year-old woman with metastatic BRAFV600E mutated colon cancer after she received combined treatment with cetuximab and encorafenib. The serum uric acid, urea nitrogen, and creatinine levels were elevated on day four of the first cycle. The fibrin degradation product (FDP) and D-dimer levels were also high. Diuresis and rasburicase were initiated for TLS, and the laboratory data all normalized on day 8. Thus, the possibility of TLS being induced by targeted drugs in patients with solid tumors, including colorectal cancer, must not be overlooked.

Risk factors for stoma prolapse after laparoscopic loop colostomy.

BACKGROUND: Stoma prolapse (SP) is a common stoma-related complication, particularly in loop colostomies. This study aimed to investigate potential risk factors for SP development after laparoscopic loop colostomy. METHODS: In total, data from 140 patients who underwent laparoscopic loop colostomy were analyzed between September 2016 and March 2022. Risk factors for SP were investigated retrospectively. RESULTS: The median follow-up duration after colostomy was 12.5 months, and SP occurred in 33 (23.6%) patients. Multivariate analysis showed that being overweight (body mass index ≥ 25; odds ratio [OR], 8.69; 95% confidential interval [CI], 1.61-46.72; p = 0.012) and having a thin rectus abdominis penetration of the stoma (< 8.9 mm; OR, 8.22; 95% CI, 2.50-27.05; p < 0.001) were independent risk factors for SP. Other patient characteristics and surgical factors associated with stoma construction were unrelated to SP development. CONCLUSIONS: Being overweight and the route penetrating the thinner rectus abdominis during stoma construction was associated with a significantly higher incidence of SP after laparoscopic loop colostomy. Selecting a construction site that penetrates the thicker rectus abdominis muscle may be crucial for preventing SP.

Risk factors for lateral lymph node metastasis based on the molecular profiling of rectal cancer.

AIM: The association between molecular profiles and lateral lymph node metastasis (LLNM) in patients with rectal cancer remains unclear. Therefore, this study aimed to identify the molecular profiles of rectal cancer associated with LLNM. METHOD: We retrospectively examined patients who underwent rectal cancer surgery with lateral lymph node dissection without preoperative treatment and whose surgically resected specimens were evaluated using multiomics-based analyses from 2014 to 2019. We compared the clinical characteristics and molecular profiles of patients with pathological LLNM (pLLNM+) with those of patients without (pLLNM-) and identified risk factors for LLNM. RESULTS: We evaluated a total of 123 patients: 18 with and 105 without pLLNM. The accumulation of mutations in genes key for the development of colorectal cancer were similar between the groups, as was the tumour mutation burden. The distribution of consensus molecular subtypes (CMS) was significantly different between the groups (p = 0.0497). The pLLNM+ patients had a higher prevalance of CMS4 than the pLLNM- patients (77.8% vs. 51.4%). According to the multivariate analysis, the independent risk factors for LLNM were a short-axis diameter of the lateral lymph node of ≥6.0 mm and CMS4; furthermore, the presence of either or both had a sensitivity of 100% for the diagnosis of LLNM. CONCLUSION: Lateral lymph node size and CMS4 are useful predictors of LLNM. The combination of CMS classification and size criteria was remarkably sensitive for the diagnosis of LLNM.

Long-term outcomes of staged liver resection for synchronous liver metastases from colorectal cancer and the clinical impact of early recurrence: A single-center retrospective cohort study.

Aim: This study was undertaken to evaluate the long-term outcomes of staged liver resection for synchronous liver metastases (SLM) from colorectal cancer (CRC), and to elucidate the prognostic impact and predictors of early recurrence (ER), which was defined as recurrence within 6 mo. Methods: Patients with SLM from CRC, except for initially unresectable SLM, from January 2013 to December 2020 were included. First, overall survival (OS) and relapse-free survival (RFS) after staged liver resection were evaluated. Second, eligible patients were classified as follows: patients who were unresectable after resection of CRC (UR), patients with ER, and patients without ER (non-ER), and their OS after resection of CRC were compared. In addition, risk factors for ER were identified. Results: The 3-y OS and RFS rates after resection of SLM were 78.8% and 30.8%, respectively. Next, the eligible patients were classified as follows: ER (N = 24), non-ER (N = 56), and UR (N = 24). The non-ER group had a significantly better OS than the ER (3-y OS: 89.7% vs 48.0%, P = .001) and UR (3-y OS: 89.7% vs 61.6%, P < .001) groups, while there was no significant difference between the ER and UR groups in OS (3-y OS: 48.0% vs 61.6%, P = .638). Increasing carcinoembryonic antigen (CEA) before and after resection of CRC was identified as an independent risk factor for ER. Conclusion: Staged liver resection for SLM from CRC was feasible and useful for oncological evaluation, as changes in CEA could predict ER, which was associated with a poor prognosis.

Long-term outcomes of upfront robotic rectal cancer surgery: a single-center, retrospective cohort study in Japan.

PURPOSE: The purpose of this study was to evaluate the long-term outcomes of robotic rectal cancer surgery and to examine the risk factors for recurrence. METHODS: In a high-volume center in Japan, we retrospectively enrolled patients with pStage I-III rectal cancer within 15 cm of the anal verge who underwent robotic surgery from 2011 to 2017. Almost all patients underwent upfront surgery, and lateral lymph-node dissection (LLND) was performed for patients with locally advanced lower rectal cancer. We evaluated the 5-year overall survival (OS), relapse-free survival (RFS), and cumulative local recurrence (LR) rates and examined the risk factors for the RFS. RESULTS: We evaluated 488 patients who underwent robotic rectal cancer surgery, including 5.1% who underwent preoperative chemoradiotherapy to obtain clear resection margins and 33.6% who underwent LLND. There were 203, 87, and 198 patients with pStage I, II, and III, respectively, and the positive resection margin rate was 1.0%. The 5-year OS, RFS, and LR rates were 95.5%, 81.7%, and 2.2%, respectively. The independent risk factors for the RFS were the presence of venous invasion, extramural tumor deposits without lymph-node structure, and pT ≥ 3. CONCLUSION: This study demonstrated the favorable long-term outcomes of robotic rectal cancer surgery.

Advantages of preoperative counseling with video for robotic rectal cancer surgery compared with conventional counseling: A randomized controlled trial.

PURPOSE: Surgeons should provide patients with appropriate explanations before surgery and obtain informed consent. However, this process requires time and effort and can be a great burden. The purpose of this study was to compare preoperative counseling with video (VC) and conventional counseling (CC) for rectal cancer patients. METHODS: Rectal cancer patients indicated for surgery were included between April 2021 and March 2022, and eligible patients were randomly assigned to the CC and VC groups. The primary outcomes were the comprehension, satisfaction, and anxiety levels, and the secondary outcome was the preoperative counseling time. This exploratory study protocol was registered with the UMIN Clinical Trials Registry (UMIN000038133). RESULTS: We included 13 patients in the CC group and 17 in the VC group. All eligible patients were scheduled for robotic rectal cancer surgery. There were no significant differences between the two groups, including patients' general condition, preoperative diagnosis, and planned procedures. Although the comprehension, satisfaction, and anxiety test scores were not significantly different between the groups, the preoperative counseling time was significantly shorter in the VC group than in the CC group (20 vs. 35 minutes, P = .002). A 4-year college degree significantly increased the counseling time, whereas VC significantly decreased it. CONCLUSION: Using videos in preoperative counseling for rectal cancer patients is useful. This novel method could reduce the burden on surgeons during preoperative counseling in the era of robotic surgery and work style reforms.

The Effectiveness of Machine Learning in Predicting Lateral Lymph Node Metastasis From Lower Rectal Cancer: A Single Center Development and Validation Study.

AIM: Accurate preoperative diagnosis of lateral lymph node metastasis (LLNM) from lower rectal cancer is important to identify patients who require lateral lymph node dissection (LLND). We aimed to create an effective prediction model for LLNM using machine learning by combining preoperative information. METHODS: We retrospectively examined patients who underwent primary rectal cancer surgery with unilateral or bilateral LLND between April 2010 and March 2020 at a single institution. Using the machine learning software "Prediction One" (Sony Network Communications), we developed a prediction model in the training cohort that included 267 consecutive patients (500 sides) from April 2010. Clinicopathological data obtained from the preoperative examinations were used as the learning items. In the validation cohort that included subsequent patients until March 2020, we compared the discriminating powers of the prediction model and the conventional method using the short-axis diameter of the largest lateral lymph node, as detected on magnetic resonance imaging. RESULTS: The area under the receiver operating characteristic curve (AUC) of the prediction model was 0.903 in the validation cohort comprising 56 patients (107 sides). This indicated significantly higher predictive power than that of the conventional method (AUC = 0.754; P = .022). Using the cutoff values defined in the training cohort, the accuracy, sensitivity, and specificity of the prediction model were 80.4%, 90.0%, and 79.4%, respectively. The model was able to correctly predict four of five sides comprising LLNM with the short-axis diameters ≤4 mm. CONCLUSION: Machine learning contributed to the creation of an effective prediction model for LLNM.

Advantages of robotic abdominoperineal resection compared with laparoscopic surgery: a single-center retrospective study.

PURPOSE: Although robotic surgery for rectal cancer can overcome the shortcomings of laparoscopic surgery, studies focusing on abdominoperineal resection are limited. The aim of this study was to compare the operative outcomes between robotic and laparoscopic abdominoperineal resection. METHODS: This retrospective cohort study was conducted from April 2010 to March 2020. Patients with rectal cancer who underwent robotic or laparoscopic abdominoperineal resection without lateral lymph node dissection were enrolled. The perioperative and oncological outcomes were compared. RESULTS: We evaluated 33 and 20 patients in the robotic and laparoscopic groups, respectively. The median operative time and blood loss were comparable between the two groups. No significant differences in the overall complication rates were noted, whereas the rates of urinary dysfunction (3% vs. 26%, p = 0.02) and perineal wound infection (9% vs. 35%, p = 0.03) in the robotic group were significantly lower in comparison to the laparoscopic group. The median postoperative hospital stay was significantly shorter in the robotic group (8 days vs. 11 days, p < 0.01). The positive resection margin rates were comparable between the two groups. CONCLUSION: Robotic abdominoperineal resection demonstrated better short-term outcomes than laparoscopic surgery, suggesting that it could be a useful approach.

Efficacy of a robotic stapler on symptomatic anastomotic leakage in robotic low anterior resection for rectal cancer.

PURPOSE: Clinical evidence demonstrating risk factors for anastomotic leakage including robotic staplers has remained limited, even though the use of robotic surgery has increased substantially. The purpose of this study was to evaluate the effects of robotic staplers on symptomatic anastomotic leakage in robotic low anterior resection for rectal cancer. METHODS: A total of 427 consecutive patients with primary rectal cancer who underwent robotic low anterior resection without diverting stoma were investigated retrospectively. Symptomatic anastomotic leakage was defined as anastomotic leakage of Clavien-Dindo Grade ≥ II. We compared the symptomatic anastomotic leakage rates between manual and robotic staplers using propensity score matching and investigated the risk factors for symptomatic anastomotic leakage. RESULTS: After propensity score matching, 168 pairs of manual and robotic stapler cases were selected. The symptomatic anastomotic leakage rate was significantly higher for manual staplers (6.5%) than for robotic staplers (1.2%, p = 0.02). In a multivariate analysis, the use of a manual stapler (p = 0.04, OR 4.86, 95% CI 1.08-21.8) and anastomosis < 4 cm from the anal verge (p < 0.01, OR 4.36, 95% CI 1.48-12.9) were identified as independent risk factors for symptomatic anastomotic leakage. CONCLUSIONS: Robotic stapler use was associated with a significantly decreased rate of anastomotic leakage in robotic low anterior resection without diverting stoma for rectal cancer.

Robotic-assisted surgery for rectal cancer with situs inversus totalis: A case report.

We present a very rare case of rectal cancer in a patient with situs inversus totalis (SIT), which is a complete transposition of the thoracic and abdominal viscera. A woman in her 60s visited a local hospital reporting bloody stool and was diagnosed with upper rectal cancer and SIT. We made careful preoperative preparations for the congenital anomaly, and robotic-assisted high anterior resection with D3 lymph node dissection was performed. Although we adopted an unusual six-port placement, the operation was performed safely and efficiently without any adverse events. The patient recovered uneventfully. The pathological specimen was classified as pT3N2bM0 with negative resection margins. Robotic-assisted surgery is advantageous for rectal cancer treatment even when anatomical abnormalities make the surgical procedure more difficult.

Changes in antimicrobial susceptibility profile and prevalence of quinolone low-sensitive strains in subgingival plaque from acute periodontal lesions after systemic administration of sitafloxacin.

This study aimed to assess changes in antimicrobial susceptibilities of subgingival bacteria in acute periodontal lesions following systemic administration of a new-generation fluoroquinolone, sitafloxacin and to monitor the occurrence and fate of quinolone low-sensitive strains. Patients with acute phase of chronic periodontitis were subjected to microbiological assessment of their subgingival plaque samples at baseline (A1). Sitafloxacin was then administered systemically (100 mg/day for 5 days). The microbiological examinations were repeated one week after administration (A2). Susceptibilities of clinical isolates from acute sites to various antimicrobials were determined using broth and agar dilution methods. At A2, subgingival bacteria with low sensitivity to levofloxacin were identified in four patients, and they were subjected to a follow-up microbiological examination at on the average 12 months after sitafloxacin administration (A3). The patients received initial and supportive periodontal therapy during the period A2 to A3. From the examined subgingival sites, 8 and 19 clinical isolates were obtained at A2 and A3, respectively. Some Streptococcus strains isolated at A2 were found to be resistant to levofloxacin (MIC 16-64 µg/ml), azithromycin (MIC 2->128 µg/ml) or clarithromycin (MIC 1->32 µg/ml). At A3, isolated streptococci were highly susceptible to levofloxacin (MIC 0.5-2 µg/ml), while those resistant to azithromycin or clarithromycin were still isolated. It is suggested that the presence of the quinolone low-sensitive strains in initially acute lesions after sitafloxacin administration was transient, and they do not persist in the subgingival milieu during the periodontal therapy.

Effects of systemic administration of sitafloxacin on subgingival microflora and antimicrobial susceptibility profile in acute periodontal lesions.

The aim of this study was to assess the effect(s) of systemic administration of sitafloxacin on subgingival microbial profiles of acute periodontal lesions. Antimicrobial susceptibility of clinical isolates was also investigated. Patients with acute phases of chronic periodontitis were subjected to clinical examination and microbiological assessment of their subgingival plaque samples by culture technique. Sitafloxacin was then administered (100 mg/day for 5 days) systemically. The clinical and microbiological examinations were repeated 6-8 days after administration. Susceptibilities of clinical isolates to various antimicrobials were determined using the broth and agar dilution methods. From the sampled sites in 30 participants, a total of 355 clinical isolates (34 different bacterial species) were isolated and identified. Parvimonas micra, Prevotella intermedia and Streptococcus mitis were the most prevalent cultivable bacteria in acute sites. Systemic administration of sitafloxacin yielded a significant improvement in clinical and microbiological parameters. Among the antimicrobials tested, sitafloxacin was the most potent against the clinical isolates with an MIC90 of 0.12 µg/ml at baseline. After administration, most clinical isolates were still highly susceptible to sitafloxacin although some increase in MICs was observed. The results suggest that systemic administration of sitafloxacin is effective against subgingival bacteria isolated from acute periodontal lesions.